1951 CA starting / electrical problem

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   Hello all, 
I've got a head scratcher here. After doing a considerable amount of work on the tractor, full tear down and rebuilt head, exhaust manifold, coolant flush, inner and outer final drive seals, pulled and cleaned hydraulic pump, repacked rams, new hydraulic hoses, rebuilt carb, new sediment bowl, oil pressure gauge, thermostat and gauge, new brakes, and lastly a new coat of Allis Persian orange. 

Original 6 volt generator and positive ground. I am having trouble with my starter. It doesn't spin or even hum. I checked for amperage at the starter terminal and have around 6.3 amps. I am using 00 gauge wire for ground and negative supply to starter. I pulled positive and wire wheeled the contacts points to ensure proper grounding. I checked ohms between positive terminal and the lock bolt hole for the starter and all is good here .3 ohms. I pulled the starter, I was able to get it to spin a few times on the bench and it had an odd grinding sound but no signs of wear.  It stopped spinning entirely after this.

Took swing arm assembly off to inspect brass button and contact points. They were in working order. 
Bendix visual inspection looks good, teeth on the drive gear are in good condition, no chipped or broken teeth (same on the fly wheel) nose cone in good condition. checked the armature Ohms where consistent in 180 test, side by side, and no continuity on the shaft - so I would say it passed. Checked the continuity on the brass button to the 2 brushes wired to it and both checked with similar ohms. 

Last test I ran I put power to the brass button without the swing arm and still nothing. 

Thinking I may have a weak battery I checked with my battery tester and it checked out with battery tester and multi meter. 

By all the test I would assume the starter is in working condition with the strange grind noise, I have power where I should and ground where I need. 

I am not interested in switching to 12 volt, I know there are some benefits but I want to try and keep it as original as possible. 

Any thoughts would be greatly appreciated.  

Edited by mosstrumpet - 20 Aug 2023 at 8:36pm

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mosstrumpet Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 19 Jul 2021 Location: South Carolina Points: 18	Post Options Post Reply Quote mosstrumpet Report Post Thanks(0) Quote Reply Topic: 1951 CA starting / electrical problem Posted: 20 Aug 2023 at 8:30pm
	Hello all, I've got a head scratcher here. After doing a considerable amount of work on the tractor, full tear down and rebuilt head, exhaust manifold, coolant flush, inner and outer final drive seals, pulled and cleaned hydraulic pump, repacked rams, new hydraulic hoses, rebuilt carb, new sediment bowl, oil pressure gauge, thermostat and gauge, new brakes, and lastly a new coat of Allis Persian orange. Original 6 volt generator and positive ground. I am having trouble with my starter. It doesn't spin or even hum. I checked for amperage at the starter terminal and have around 6.3 amps. I am using 00 gauge wire for ground and negative supply to starter. I pulled positive and wire wheeled the contacts points to ensure proper grounding. I checked ohms between positive terminal and the lock bolt hole for the starter and all is good here .3 ohms. I pulled the starter, I was able to get it to spin a few times on the bench and it had an odd grinding sound but no signs of wear. It stopped spinning entirely after this. Took swing arm assembly off to inspect brass button and contact points. They were in working order. Bendix visual inspection looks good, teeth on the drive gear are in good condition, no chipped or broken teeth (same on the fly wheel) nose cone in good condition. checked the armature Ohms where consistent in 180 test, side by side, and no continuity on the shaft - so I would say it passed. Checked the continuity on the brass button to the 2 brushes wired to it and both checked with similar ohms. Last test I ran I put power to the brass button without the swing arm and still nothing. Thinking I may have a weak battery I checked with my battery tester and it checked out with battery tester and multi meter. By all the test I would assume the starter is in working condition with the strange grind noise, I have power where I should and ground where I need. I am not interested in switching to 12 volt, I know there are some benefits but I want to try and keep it as original as possible. Any thoughts would be greatly appreciated. Edited by mosstrumpet - 20 Aug 2023 at 8:36pm

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steve(ill) Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 11 Sep 2009 Location: illinois Points: 81066	Post Options Post Reply Quote steve(ill) Report Post Thanks(0) Quote Reply Posted: 20 Aug 2023 at 10:56pm
	If starter is on the bench and you put power to the brass button and ground the case.. It should spin.. dont matter what the bendix is doing... Its just a motor at that point.. If it does not spin, then you have a bad battery or internal problems... Grinding noise makes me think the starter needs rebuilt.. If the grinding is not in the bearing / bushings on the end of the shaft, then the rotor is rubbing the magnets as it rotates. If you want to verify the battery, jump the starter with your 12v truck battery as a " test". I was able to get it to spin a few times on the bench and it had an odd grinding sound but no signs of wear. It stopped spinning entirely after this. Edited by steve(ill) - 20 Aug 2023 at 10:58pm
	Like them all, but love the "B"s.

steve(ill) Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 11 Sep 2009 Location: illinois Points: 81066	Post Options Post Reply Quote steve(ill) Report Post Thanks(0) Quote Reply Posted: 20 Aug 2023 at 11:01pm
	i have taken "WEAK" starters apart, sanded the commutator smooth and clean on a lathe, scraped the insulator betweeen the bars with a sharp thin knife, sanded the brushes flat on the face, make sure the SPRINGS are pushing on the brushes, oil the bearing and reassemble....... Not a " rebuild" , but often works.
	Like them all, but love the "B"s.

Ted in NE-OH Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 12 Nov 2009 Location: Austinburg OH Points: 1703	Post Options Post Reply Quote Ted in NE-OH Report Post Thanks(0) Quote Reply Posted: 21 Aug 2023 at 9:08am
	Could be that new paint is keeping you from getting a good ground at the starter.
	CA, WD, C, 3 Bs, 2 Gs, WC, I-400, 914

TramwayGuy Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 19 Jan 2010 Location: Northern NY Points: 11445	Post Options Post Reply Quote TramwayGuy Report Post Thanks(0) Quote Reply Posted: 21 Aug 2023 at 9:19am
	“.. If the grinding is not in the bearing / bushings on the end of the shaft, then the rotor is rubbing the magnets as it rotates.” I had a starter that had a broken armature, and it would spin sometimes, but with heavy dragging. Acted like bad bushings.

MACK Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 17 Nov 2009 Points: 7664	Post Options Post Reply Quote MACK Report Post Thanks(0) Quote Reply Posted: 21 Aug 2023 at 9:33pm
	Brushes may not making good contact with armature. Worn, weak springs, or stuck. MACK

Steve in NJ Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Location: Andover, NJ Points: 11791	Post Options Post Reply Quote Steve in NJ Report Post Thanks(0) Quote Reply Posted: 23 Aug 2023 at 7:26pm
	If you have a grinding going on inside, best to have a rebuilder tear it down and access the problem. Do you have a good reliable rebuilder in town? If not, I offer rebuilding services if interested.... Steve@B&B bb-customcircuits.com
	39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife